


it's knot a sin

by Milkynubs



Series: A Universe in Which Cumming is Ten Times More Tedious [2]
Category: Undertale (Video Game)
Genre: Crushes, Excessive Orgasms in general actually, Excessive Semen, Gen, Knotting, Long Orgasms, Masturbation, Sexual Frustration, pillow-humping
Language: English
Status: Completed
Published: 2016-05-07
Updated: 2016-05-07
Packaged: 2018-06-06 21:23:01
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 723
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6770434
Author URL: https://archiveofourown.org/users/Milkynubs/pseuds/Milkynubs
Summary: <blockquote class="userstuff">
              <p>Sans learned from his mistake and does his business in private this time.</p>
            </blockquote>





	it's knot a sin

**Author's Note:**

> ive always hated knots??? but with sans theyre like the hottest thing?? same with shit like daddy kink what has this (asexual!!!) skeleton done to me

Papyrus is out, you're working, Sans got off work and after chatting with you he's ready to get off in a different sense.

Finally.

It's been two weeks since he last came. He didn't want to risk you or Papyrus catching him or risk looking like an idiot in front of you again, and even when Papyrus was distracted by something for hours at a time, Sans feared the worst case scenarios. After all, you came to visit him at work while he was in the middle of an (absolutely fuckin' _killer_ ) orgasm of all times, who's to say Papyrus won't finish a cooking lesson early or get too bored of TV, or decide to make dinner that he expects Sans to join him for, or maybe Mettaton will decide it's time for a "Happy Break Time" just as Sans is teetering over the edge… You get the idea. Papyrus is an adult now and can entertain himself, but you never know. He's barged in many a time for all sorts of reasons.

Plus on Sans's breaks and days off, you'd get concerned if he didn't show up to Grillby's. You respect his privacy, of course, but he doesn't want you to come to any conclusions.

There are still plenty of things that _could_ happen, but it's been two weeks of longing and dreaming with no release. He gets a boner from your scent by this point, and that needs to stop before he gets a stiffy in the middle of Grillby's (again. Luckily no one noticed, probably).

He's gotten comfortable on his bed, leaning back against a propped-up pillow. He pulls down his shorts to release The Beast, which is already standing at full attention, twitching and leaking with a partially-swollen knot. He could probably come from a gentle breeze, which isn't terribly uncommon for a pent-up monster, actually. He wonders if you ever have this problem, and a large drop of precum trickles from his tip at the thought.

Tissue box at the ready, he jerks himself off and it takes only ten seconds to reach his climax. He quickly soaks through the first tissue, and his hand becomes messy as cum slides down his cock despite his efforts to avoid a mess. A powerful jet actually tears the fragile wet paper and he has to rush to replace it before he comes on himself or his sheets. In the privacy of his own room, he allows himself to cry out, to pant like a dog, to whine and chant your name with his tongue lolling out involuntarily. It's an indescribable high, the most intense pleasure he's felt, but it's still not enough, because it's not _you_.

To hell with the tissues, he decides, turning and grabbing the pillow and not hesitating to mount it. It's better, it's enough for him to pretend he's touching you, but the _squeeze_ isn't there. So to hell with his dignity too, he decides, folding the pillow around his cock.

This can't be what sex "really" feels like, but being a virgin he can't tell the difference and so it's _just enough_ , when he squeezes his eyes shut it's like the sides of the pillow he's grasping are your hips and you're unconsciously trying to take hold of his knot and trap him inside, his speed becomes rabbit-like and he doesn't even realize he's screaming and then he finally decides to tie with you and he slams one final time, forcing his huge knot inside, head back, panting, still coming, still coming, it's so good, he's filled you completely and cum is forced to leak past his knot to prevent you from bursting…

…Well, no, cum is actually dripping out from the pillow he drenched, but he didn't want to remember that yet.

There are those last few weak spurts before he's spent, and he just kind of… falls forward, face-planting into the sheets as he releases the (ruined) pillow. It wasn't sex with you, but the release was still so blissful that he genuinely smiles, probably goofily, as he starts to drift off. His cock is still out, his cum is visible on the pillow that was pushed aside to the floor, and his shorts are around his ankles, but he's so tired he just has to hope Papyrus won't walk in anytime soon.

**Author's Note:**

> back at it again with knotty sans
> 
> in this universe monsters have the means to both penetrate and be penetrated when they wanna. they're made of magic ffs so why not
> 
> also unrelated but why would you stick human tits and a vagina on a lizard when you can have a cloaca housing a couple of snake dongs as well as a dong receptacle
> 
> maybe I should write alphyne smut i havent seen much not-sans porn but i'm already tired of fish and lizard with human tits/vagina (no offense if you like it just. Boooring)


End file.
